Saturable reactor device



Sept; 14, 1954 F. G. LOGAN 2,689,328

SATURABLE REACTOR DEVICE Filed Dec. 1, 1950 n n rh r'- Q z 48 46 a2 as IJ l 122 44 I 58 50; 566 l F l -1 4O 7 1- 52- l l -55 l '64 FIG. I 24 5462 26 i 0 0 5 SIGNAL SIGNAL SOURCE SOURCE SIGNAL SIGNAL 2 INVENTOR.

FRANK G. LOGAN BY I A ATTORN EY Patented Sept. 14, 1954 UNITED STATESATENT OFFICE I ers Incorporated, Detroit, Mich., a corporation ofMichigan Application December 1, 1950, Serial No. 198,609

Claims.

This invention relates to power transmission and more particularly toinductive reactor elements.

Saturable reactors usually comprise a power winding or windings on oneor more legs of a magnetic core and one or more control windings on thesame or other legs of the core. The object of the control windings is tocontrol the permeability of the core by means of auxiliary magnetomotiveforces and thereby to ultimately control the current through the powerwindings, that is, the reactor output. In conventional saturablereactors with a plurality of control windings it has been the practiceto so locate the control windings that their magnetic circuits arelinked and coincide with the magnetic circuit of the power winding so asto affect the saturation of the entire power magnetic circuit. In suchre actors which employ a plurality of control windings for mixingsignals in a common amplifier,

undesirable interaction between the separate signal windings isunavoidable because of the inductive coupling therebetween due toconventional core structures.

In accordance with one embodiment of this invention an integral corestructure is arranged to carry a plurality of control windings in such away as to form a plurality of magnetic control circuits isolated fromeach other but linked to the magnetic circuit of a power winding wherebyeither or both of the control windings are effective to control theoutput of the power winding without any appreciable interaction betweenthe control windings.

t is therefore an object of this invention to provide a new and usefulinductive reactor control apparatus with a multiplicity of controlwindings having a minimum of interaction'therebetween.

Another object of the invention is to provide a reactor with a pluralityof control windings inductively isolated from each other.

A further object of the invention is to provide a reactor with aplurality of control windings whose respective magnetic circuits areisolated from each other.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing wherein a preferred form of the present invention isdiagrammatically shown.

In the drawing:

Fig. 1 is a diagram of a simple inductive reactor control apparatusillustrating the invention; and Fig. 2 is a diagram illustrating afurther application of the invention.

Referring now to Fig. l, a saturable reactor It, connected in aself-saturating magnetic amplifier circuit, controls the power suppliedto a load I2 from an A. C. source [4 through a one way valve It and apower winding I8 of the saturable reactor It. The power winding [8 iswound on a leg 20 of a core 22, and the inductance and consequentimpedance of the winding i8 is determined by the permeability or fluxcondition of the core 22 which may be controlled by one or both of apair of control coils 24 and 26 wound on portions of the core 22 andsupplied with control current from separate sources 2% and 3drespectively. The core structure and position of the winding is suchthat although the magnetic circuit of the power winding It is coupled tothe magnetic circuits of the windings 2t and 26 and is changeable inresponse to the variation in the magnetic circuits of the windings 2tand 26, the latter windings are substantially isolated inductively fromeach other and there is substantially no interaction between themagnetic circuits of the coils 24 and 26.

To prevent undesirable interaction between the control circuits of thewindings 24 and it, the magnetizable core 22, preferably of laminatedcore material, has three magnetic circuits whose paths arediagrammatically indicated by the closed dotted loops S2, 34, and 36,and which are formed by various closed combinations of the many sectionsof the core. These combinations define three core windows 38, it and 42.

The magnetic circuit 32 of the power winding I 8 is formed by the coresections it, at, it, and 50; the magnetic circuit 3d of the controlwinding 24 is formed by the core sections 52, 5%, 56, and a portion 58of the section it; and the magnetic circuit 38 of the control winding 26is formed by core sections 88, [52, 6t, and a portion 66 of the section55. Suitable currents are supplied through the control coils 24 and itby the control current sources 28 and (it to provide any desirabledegree and type of impedance control of the main winding 18.

Since magnetic circuits tend to conform to the paths of leastreluctance, the magnetic circuits of the respective windings will followthe indicated dotted paths with very slight leakage or deviation. Thusit will be seen that although both control magnetic circuits 3 5 and 36link the power magnetic circuit 32, they do not link each other, i. e.they are not coupled to each other. Thus there will be substantially nointeraction between the control windings 24' and 26.

Although the half-wave circuit of Fig. 1 serves to explain the inventionand is an operable circuit,

it finds more practical use when used as one of a plurality of suchunits connected to form more practical amplifiers, as for example theDoubler self-saturating magnetic amplifier diagrammatically shown inFig. 2, wherein each of the units A and B is similar to the circuit ofFig. l; the two units, howeven-being connected in reverse relation toeach other to provide an A, C. output into the load. Each of the units Aand B is provided with a reactor core 22 similar to that in Fig. 1 withsignal windings 24 and 2B inductively isolated from each other, bothhowever being inductively coupled to the power winding IS in order toaifect the impedance thereof.

While the form of embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. A saturable reactor comprising a saturable core having core sectionsdefining a plurality of magnetic paths to provide gapless magneticcircuits for windings on the core, one of said paths having first andsecond portions, a power winding for insertion as series impedancebetween a source of power and a load, said power winding embracing acore section of said one path and having substantially its entiremagnetic circuit in said core restricted to a path fully intercepted byeach of said portions, a first control winding embracing a core sectionof a second path, said first portion being integral with a portion ofthe second path whereby the first control winding is operable to controlthe saturation of said first portion when control current is supplied tothe first control winding, a second control winding embracing a coresection of a third path, said second portion being integral with aportion of the third path whereby the second control winding is operableto control the saturation of said second portion when control current issupplied to the second control winding, the respective core sectionscarrying said control windings being sub-- stantially isolatedmagnetically from each other to prevent inductive interaction betweensaid control windings, saturation change of either said first or secondportions by the control windings being operable to change the reluctanceof the power winding magnetic circuit thereby to change the impedance ofthe power winding.

2. Reactor control apparatus comprising a source of electrical power, aload circuit, a saturable core having sections defining a plurality ofmagnetic paths to provide magnetic circuits for windings on the core,one of said paths having portions common to portions of the other paths,said other paths being magnetically isolated from each other, a powerwinding linking said one path and being connected in series with saidpower source and said load circuit, the magnetic circuit of said powerwinding being confinedat all times to a magnetic path passing througheach of said common portions in series succession, a plurality ofcontrol coils, each control coil exclusively embracing a different oneof said other paths whereby undesirable interaction between the controlcoils is avoided, the respective control coils being connected toseparate sources of control current, each control coil being adapted tocontrol the saturation of the core portion common to its associated pathand said one path, thereby to change the reluctance of the power windingmagnetic circuit in order to change the impedance of the power windingto current flow from said power source to said load circuit.

3. Reactor control apparatus comprising a source of electrical power, aload circuit, a rectifier, a saturable core having sections defining aplurality of magnetic paths to provide magnetic circuits for windings onthe core, one of said paths having portions common to portions of theother paths, said other paths being magnetically isolated from eachother, a power winding linking said one path and being connected inseries with said rectifier, said power source and said load circuit in aself-saturating arrangement, the magnetic circuit of said power windingbeing confined at all times to a magnetic path passing through each ofsaid common portions in series succession, a plurality of control coilsrespectively embracing a different one of said other paths wherebyundesirable interaction between the control coils is avoided, therespective control coils being connected to separate sources of controlcurrent, each control coil being adapted to control the saturation ofthe core portion common to its associated path and said one path,thereby to change the reluctance of the power winding magnetic circuitin order to change the impedance of the power winding to current fiowfrom said power source to said load circuit.

4. Reactor control apparatus comprising an electrical line connected toa source of power, and a saturable reactor comprising a saturable corehaving core sections defining a plurality of magnetic paths to providemagnetic circuits for windings on the core, one of said paths havingfirst and second portions, a power winding embracing a core section ofsaid one path and having substantially its entire magnetic circuit insaid core restricted to a path fully intercepted by each of saidportions, said power winding being connected in series with said line, afirst control winding embracing a core section of a second path, saidfirst portion being integral with a portion of the second path wherebythe first control winding is operable to control the saturation of saidfirst portion, a second control winding embracing a core section of athird path, said second portion being integral with a portion of thethird path whereby the second control winding is operable to control thesaturation of said second portion, the respective core sections carryingsaid control windings being substantially isolated magnetically fromeach other to prevent inductive interaction between said controlwindings, saturation change of either said first or second portions bythe control windings being operable to change the reluctance of thepower winding magnetic circuit thereby to change the impedance of thepower winding in order to control the amount of current flow from saidsource through said line.

5. Reactor control apparatus comprising an electrical line connected toa source of power, a rectifier, and a saturable reactor comprising asaturable core having core sections defining a plurality of magneticpaths to provide magnetic circuits for windings on the core, one of saidpaths having first and second portions, a power winding embracing a coresection of said one path and having substantially its entire magneticcircuit in said core restricted to a path fully intercepted by each ofsaid portions, said power winding being connected in series with saidline and said rectifier in a self-saturating arrangement, a firstcontrol winding embracing a core section of a second path, said firstportion being integral with isolated magnetically from each other toprevent l0 inductive interaction between said control windings, andseparate sources of control current for said control windings,saturation change of either said first or second portions by the controlwindings being operable to change the reluctance of 15 the power windingmagnetic circuit thereby to change the impedance of the power winding inorder to control the amount of current flow from said source throughsaid line.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,793,213 Dowling Feb. 17, 1931 2,425,622 Kromiller Aug. 12,1947 OTHER REFERENCES Westinghouse Engineer (vol. 10, Issue 5) (page202, relied on).

